1. Field of the Invention
The present invention relates to a wafer ring supplying and returning apparatus.
2. Prior Art
The wafer ring supplying and returning apparatus in a die bonding apparatus is generally equipped with a magazine that accommodates wafer rings at a fixed pitch, an elevator that moves the magazine up and down, and a wafer ring conveying means. The wafer ring conveying means conveys wafer rings accommodated in the magazine one at a time and supplies the wafer rings to a jig holder, and it also returns used wafer rings from which the dies have been picked up to empty accommodating sections in the magazine.
A wafer sheet is, at its outer circumferential portion, attached to each of the wafer rings, and a wafer that has been split longitudinally and laterally into dies is pasted to the wafer sheet.
The wafer rings that are supplied to the jig holder are stretched by a stretching device so as to enlarge the spacing between the dies. As a result, the wafer sheets on the used wafer rings are in a slack state. If such used wafer rings are returned to the magazine xe2x80x9cas isxe2x80x9d, these used wafer rings will interfere with the adjacent wafer rings above or below that are accommodated in the magazine. Accordingly, before these used wafer rings are returned to the magazine, a warm air draft is blown onto the wafer sheets so that the wafer sheets are caused to contract.
Thus, since the used wafer rings are returned to the magazine after a warm air draft is blown onto the wafer sheets so as to contract, and the next wafer sheet is then removed from the magazine, it is time consuming.
In order to solve this problem, in the die bonding apparatus disclosed in, for example, in Japanese Patent Application Laid-Open (Kokai) No. 2000-277545, the working efficiency of die bonding is improved by performing an operation that causes the wafer sheets on the used wafer rings to contract during the die bonding operation.
In order to cause contraction of the wafer sheets on the used wafer rings, this prior art bonding apparatus includes, a hot-plate upper waiting section, a lower wafer waiting section, and a lower X-axis slider mechanism. The hot-plate upper waiting section is disposed above the side of a magazine so as to be raised and lowered by an upper waiting location raising-and-lowering part. The lower wafer waiting section is disposed on the front side of the magazine in a position that is lower than the height at which the wafer rings are removed from the magazine. The lower X-axis slider mechanism causes a lower X-axis hand that returns the wafer rings in this lower wafer waiting section to the magazine to move in the direction of the X axis. Since a large number of constituting mechanical elements are required, the apparatus is complicated and expensive, and the size of the apparatus tends to be large.
In operation of this apparatus, the wafer rings are held by an upper X-axis hand and removed from the jig holder, after which the wafer rings are caused to wait in the hot plate upper waiting section. The hot plate upper waiting section is next lowered so that the wafer ring is placed on the hot plate, and the magazine is lowered and the hot plate is stopped at the height of the lower wafer waiting section. Then, the magazine is raised so that the original accommodating section, which is empty, is set at the height of the lower wafer waiting section. Lastly, the wafer ring whose wafer sheet has been caused to contract by the application of heat from the hot plate is accommodated in the specified accommodating section of the magazine by the lower X-axis hand. Thus, an extremely large number of operations are required; and as a result, the control system is complicated.
Accordingly, the object of the present invention is to provide a wafer ring supplying and returning apparatus that causes contraction of the wafer sheets of the used wafer rings during the bonding performed by the die bonding apparatus and simplifies the apparatus and the control system, thus lowering the cost and reducing the size of the apparatus.
The above object is accomplished by a unique structure for a wafer ring supplying and returning apparatus that comprises:
a magazine which is carried on an elevator and raised and lowered, the magazine accommodating wafer rings at a fixed pitch,
a jig holder which holds the wafer rings and being moved between a wafer ring exchange position in front of the magazine and a die pick-up position,
a drier which is disposed near a front of the magazine, the dryer blowing a hot air draft upward,
a buffer mechanism which has buffer sections in which two (upper and lower) wafer supporting grooves that support the wafer rings are formed vertically, the buffer mechanism being caused to move to above and to a front of the magazine, and
a wafer transfer mechanism which includes a wafer chucking member and a wafer pushing member, the wafer chucking member being disposed in a position corresponding to one of the upper and lower wafer supporting grooves and chucking and conveying the wafer rings, and the wafer pushing member being disposed in a position corresponding to another one of the upper and lower wafer supporting grooves and pushing the wafer rings; and in this wafer ring supplying and returning apparatus
when the jig holder has moved to the die pick-up position, an unused wafer ring inside the magazine is chucked by the wafer chucking member, removed from the magazine and supported in one of the upper and lower wafer supporting grooves of the buffer sections,
when the jig holder has moved to the wafer ring exchange position, a used wafer ring held in the jig holder is pushed by the wafer pushing member and supported in another one of the upper and lower wafer supporting grooves of the buffer sections, and the unused wafer ring inside the buffer sections is chucked by the wafer chucking member and held in the jig holder, and
when the jig holder has again moved to the die pick-up position, the buffer sections are moved to a point above the drier, and then the wafer chucking member chucks the used wafer ring inside the buffer sections and accommodates the used wafer ring in an empty accommodating section of the magazine.